Heretofore, as a membrane material for a membrane structure building, an ethylene/tetrafluoroethylene copolymer (hereinafter sometimes referred to as “ETFE”) sheet has been used (Patent Document 1).
A membrane material is, for example, fixed to a frame in the form of a quadrangle or the like and used as a membrane panel.
As a membrane panel, a tension type which is fixed to a frame in a planar shape by applying a tensile force from the periphery of the membrane material, or a cushion type such that two sheets of the membrane material are attached to a frame, and a space between the two sheets of the membrane material is filled with the air to inflate the sheets thereby to impart a tension to the membrane material, has been known.